Freezing and collapse of flexible polymers

TL;DR

This study investigates the separate freezing and collapse transitions of flexible polymer chains on lattice models, revealing that these transitions remain distinct even at infinite chain lengths due to the short-range interactions.

Contribution

It provides evidence that, unlike bond-fluctuation models, the freezing and collapse transitions do not merge in the thermodynamic limit for the lattice models studied.

Findings

Transitions remain separated at infinite chain length

Short-range interactions influence transition behavior

Contrasts with bond-fluctuation model results

Abstract

We analyze the freezing and collapse transition of a simple model for flexible polymer chains on simple cubic and face-centered cubic lattices by means of sophisticated chain-growth methods. In contrast to bond-fluctuation polymer models in certain parameter ranges, where these two conformational transitions were found to merge in the thermodynamic limit, we conclude from our results that the two transitions remain well-separated in the limit of infinite chain lengths. The reason for this qualitatively distinct behavior is presumably due to the ultrashort attractive interaction range in the lattice models considered here.